F-35 makes a lot of sense for the Marines, but frankly, I don’t quite get it’s purpose in other services. It’s like it’s trying to do too much at once, like it’s an F-16/F-117/A-10/AV-8 all rolled into one, but without the F-16s dogfighting record, without the F-117s bomb capacity, or the A-10s huge gun.
McNamara tried to make the F-111 the joint USAF/USN fighter bomber of its time in the 1960s. It failed miserably with Navy carrier tests and was just not a fighter, not matter how much $$$$$ DoD dumped into it.
As a result, the USAF got the F-111 as a medium bomber, and the Navy ultimately got the F-14 in its place, which worked out very well for both services.
There are different versions, just like there were of the F-111. Only more so. The Marines, and the Brits at least, want the STOVL version. The other services will want CTOL, with the Navy wanting theirs to be carrier capable. All versions will share many systems and parts, but will be different aircraft. The AF will have the biggest paylond and/or longest range. The Marines the smallest/shortest, with the Navy's in between somewhere. Only the STOVL versions would have the heavy weight penalty of the extra powered lift devices.
But nobody gets the GAU-8. Mores the pity.